Pesticides are designed to be effective when the target is either feeding or in contact with a compound that can be transdermal in its effect. Chemical pesticides have been known and used for years. More recently, biopesticides have been introduced that exhibit parasitic or infective control of a number of species. Effectiveness is generally measured by the power of a pesticide to lower a pest population through lethal control.
Adjuvants are presently used in the industry to enhance or modify the chemical and/or physical characteristics of pesticides. Adjuvants generally have no pesticidal activity of their own. Because of the importance of spray application of pesticides, the use of adjuvants reduces application problems such as chemical stability, incompatibility, solubility, suspension, foaming, drift, evaporation, volatilization, phytotoxicity, surface tension, droplet size and coverage. Adjuvants can, depending upon their type, enhance wetting, spreading, sticking, emulsifying, and dispersing.
A new mode of pest control is growing in use wherein pests are managed by translocation or repellency rather than by lethal measures. This approach provides the advantage of reducing the probability of adaptation by the target species. In particular, because the target is not killed, the probability of two resistant individuals finding each other and mating is significantly reduced to the random probability of the genetic variant. Additional benefits of repellency include maintenance of the ecological balance in the location of use without the negative effect of the pest. Thus in some situations, repellency is a preferred method of long-term pest management.
Repellents are often targeted against a narrow list of target pests, under rather specific application conditions. For example, the compound 9,10-anthraquinone is known to be a powerful antifeedant for bird species. Birds will not feed on seed that contains as little as 0.1% 9,10-anthraquinone by weight. The lower limit of detection in birds is as low as 125 ppm, which is the threshold where birds begin to sense the repellency. Thus the presence of 9,10-anthraquinone is known to prevent birds from eating a material that the bird might otherwise consume.
It may also be desirable in some circumstances to prevent, in a non-lethal manner, a bird from occupying or roosting on a specific site, and means for doing this in a non-lethal manner are much sought after. Pigeons are routinely killed in cities to counter the health and maintenance problems created by their feces, but it is frequently preferable to merely drive the birds away. U.S. Pat. No. 6,328,986 provides a method for deterring birds from roosting or perching on plant and structural surfaces.
There is a need, however, for a performance aid that increases the transferability of the active compound from the applied surface to the pest animal of interest, while also remaining adhered to the surface.
If a coating could be created that would be easy to apply, nontoxic to animals and humans and have increased repellent characteristics, pest animal populations could be kept at a tolerable level without resorting to lethal population control. Thus there is a need for a more efficient, non-toxic, non-lethal means of repelling pest animals from designated areas.